Simulations were carried out for studying the periodic phase separation of a symmetric binary polymer blend on the basis of Cahn-Hilliard-Cook theory. The time dependent interaction parameter x（τ） was assumed to un...Simulations were carried out for studying the periodic phase separation of a symmetric binary polymer blend on the basis of Cahn-Hilliard-Cook theory. The time dependent interaction parameter x（τ） was assumed to undergo a step-wise oscillation. The hierarchic structures composed of both large and small domains were obtained. The mechanism of the periodic formation of hierarchic structures was also demonstrated.展开更多
Even though radio broadcasting is one of the most widespread electronic mass media, its management for survival is getting drastic. The competition among incumbent radio stations becomes challenging due to the market ...Even though radio broadcasting is one of the most widespread electronic mass media, its management for survival is getting drastic. The competition among incumbent radio stations becomes challenging due to the market change and environmental evolution. Managing program quality is a critical issue to a radio station to sharpen its competitive advantages. Quality management of radio programs is intertwined with complicated factors. In order to identify the primary factors affecting radio program quality as well as explore the impact level these factors bring, this study adopts modified Delphi method and analytic hierarchy process （AHP） to explore the issues. According to the outcomes modified Delphi method, the factors were categorized into four dimensions： operation, coordination, structure, and improvement. Ten sub-dimensions were followed. Each sub-dimension includes six to nineteen indicators for measuring radio program quality. In total, 72 indicators were identified. The AHP result revealed that the most important weight was given to the operation dimension. On the contrary, the least important weight was placed on the improvement dimension. Among the sub-dimensions, the standard procedure and organizational design were rated more important than the rest. The results could provide some facts to radio managers for future management.展开更多
The flight dynamics model of air-breathing hypersonic vehicles （AHVs） is highly nonlinear and multivariable cou- pling, and includes inertial uncertainties and external disturbances that require strong, robust, and ...The flight dynamics model of air-breathing hypersonic vehicles （AHVs） is highly nonlinear and multivariable cou- pling, and includes inertial uncertainties and external disturbances that require strong, robust, and high-accuracy controllers. In this paper, we propose a linear-quadratic regulator （LQR） design method based on stochastic robustness analysis for the longitudinal dynamics of AHVs. First, input/output feedback linearization is used to design LQRs. Second, subject to various system parameter uncertainties, system robustness is characterized by the probability of stability and desired performance. Then, the mapping rela- tionship between system robustness and LQR parameters is established. Particularly, to maximize system robustness, a novel hybrid particle swarm optimization algorithm is proposed to search for the optimal LQR parameters. During the search iteration, a Chernoff bound algorithm is applied to determine the finite sample size of Monte Carlo evaluation with the given prohabilily levels. Finally, simulation results show that the optimization algorithm can effectively find the optimal solution to the LQR parameters.展开更多
文摘Simulations were carried out for studying the periodic phase separation of a symmetric binary polymer blend on the basis of Cahn-Hilliard-Cook theory. The time dependent interaction parameter x（τ） was assumed to undergo a step-wise oscillation. The hierarchic structures composed of both large and small domains were obtained. The mechanism of the periodic formation of hierarchic structures was also demonstrated.
文摘Even though radio broadcasting is one of the most widespread electronic mass media, its management for survival is getting drastic. The competition among incumbent radio stations becomes challenging due to the market change and environmental evolution. Managing program quality is a critical issue to a radio station to sharpen its competitive advantages. Quality management of radio programs is intertwined with complicated factors. In order to identify the primary factors affecting radio program quality as well as explore the impact level these factors bring, this study adopts modified Delphi method and analytic hierarchy process （AHP） to explore the issues. According to the outcomes modified Delphi method, the factors were categorized into four dimensions： operation, coordination, structure, and improvement. Ten sub-dimensions were followed. Each sub-dimension includes six to nineteen indicators for measuring radio program quality. In total, 72 indicators were identified. The AHP result revealed that the most important weight was given to the operation dimension. On the contrary, the least important weight was placed on the improvement dimension. Among the sub-dimensions, the standard procedure and organizational design were rated more important than the rest. The results could provide some facts to radio managers for future management.
基金the National Natural Science Foundation of China （No. 11672235）
文摘The flight dynamics model of air-breathing hypersonic vehicles （AHVs） is highly nonlinear and multivariable cou- pling, and includes inertial uncertainties and external disturbances that require strong, robust, and high-accuracy controllers. In this paper, we propose a linear-quadratic regulator （LQR） design method based on stochastic robustness analysis for the longitudinal dynamics of AHVs. First, input/output feedback linearization is used to design LQRs. Second, subject to various system parameter uncertainties, system robustness is characterized by the probability of stability and desired performance. Then, the mapping rela- tionship between system robustness and LQR parameters is established. Particularly, to maximize system robustness, a novel hybrid particle swarm optimization algorithm is proposed to search for the optimal LQR parameters. During the search iteration, a Chernoff bound algorithm is applied to determine the finite sample size of Monte Carlo evaluation with the given prohabilily levels. Finally, simulation results show that the optimization algorithm can effectively find the optimal solution to the LQR parameters.
